primality


Alexa's Conjecture on Primality ★★

Author(s): Alexa

Definition   Let $ r_i $ be a non negative integer such that :

$$(2i+1)^{p-1} \equiv r_i \pmod p ~~\text{ and } ~ r_i < p  , ~\text{where}~ i , p \in \mathbb{N} $$
Conjecture   Natural number $ p $ ; $ (p \geq 8) $ is a prime iff
$$ \displaystyle \sum_{i=1}^{\left \lfloor \frac{\sqrt[3]p}{2} \right \rfloor} r_i = \left \lfloor \frac{\sqrt[3]p}{2} \right \rfloor $$

Keywords: primality

Giuga's Conjecture on Primality ★★

Author(s): Giuseppe Giuga

Conjecture   $ p $ is a prime iff $ ~\displaystyle \sum_{i=1}^{p-1} i^{p-1} \equiv -1 \pmod p $

Keywords: primality

MacEachen Conjecture

Author(s): McEachen

Conjecture   Every odd prime number must either be adjacent to, or a prime distance away from a primorial or primorial product.

Keywords: primality; prime distribution

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